I have been building my Spot On for a month. The weather has been awful here in Virginia, with all this "global warming" I haven't been in a hurry to finish it.

Here is a list of what I have done and modifications.

I just bought the Spot On in Jan 2010 and when I got it home it was the original not the newer version???? I was going to return it but after checking it I found that all the covering was perfect and al the wings and fuselage were perfectly straight. So I kept it

1. Like all my ARF's, I epoxy (30 min) the inside of the nose around the firewall. They sometimes just hot glue this??? Then I thin epoxy with alcohol and paint the entire section from the fire wall to the cockpit bulkhead. This strenghtens and fuel proofs the area. I also paint the outside of the firewall and the edges to seal it and the covering edges. I then paint all the stringer joints and around the edges of all the landing gear and all the support structures servo trays etc. For god measure I spray the inside of the nose with fuel proofing clear coat. I tend to have my models for a long time and feel that the little added weight is better than having everything get fuel soaked over 200 -300 flights. I have several planes that have over 500 flights.

2. Then I reinforced the wood area around the landing gear base with triangle balsa strips & epoxy. This makes it much stronger so it won't break out on a so, so landing. I realize that a hard landing will tear up the fuselage but that's why we practice landings. I can probably be rebuilt?

3. I use Radio South CA hinges , they are stronger than the cheap CA hinges that come with most ARF's, on the ailerons and elevator and pivoy point hinges on the rudder. I like to use pivot points everywhere but the elevator was too thin and in a pattern plane the aileron throws are so small so there is little stress. However I'll never use CA hinges on a rudder again. Too much stress and I have had 4 rudders almost come off from torn CA hinges.[:'(]

4. I mounted Futaba S 3151 servos in the wing. I hade to block them up a bit since they are deeper than the wing. They touched the covering. That's why the new version has them mounted sideways...

5. I did not like the quality of the pull/pull hardware so I use the Dubro 4/40 pull/pull system.

6. Also, like all my ARF's I epoxy paint the inside of the cowl and wheel pants for strength.

7. I'll change the wheels to Dubro 2 1/4" lights and reverse the axil screw so the lock nut is on the outside vs. inside the pants.

8. I did use the elevator setup recommended. Seems very simple and it works.

9. I used Hitec 5485's on the elevator and rudder.

10. I mounted an O.S. 55 AX with a pitts mufffler ( 16.6 oz) horizontally. This lined up the the throttle pushrod perfectly but I did have to use the GP dead center long drill to drill a hole in the inside partial bulkhead to thread it through.

11. Oh. before I epoxied the belly pan on I did fill in the forward and aft lightening holes with light balsa sheeting. So I don't punch my finger through the covering[&o] when installing the wing.

12. Since I'm still using 72 mgz radios I installed an antenna tube inside the fuselage. I also split the ailerons into two channels as flapperons.

13. When I checked the wing and tail feathers allignment with my laser light they were perfect. I'm glad I kept the kit.

I still have a few things to do and will include some pictures when I'm finished. I'll decide on the fuel line system after I cut the cowl?

Now if we can get rid of the snow and get some temperatures above 45* I'll get excited about finishing and flying this plane.

I think I may have found a solution to running the 4 Stroke inverted and having the fuel tank mounted above the engine = a fuel regulator http://www.ironbaymodelcompany.com/i...es/Page438.htm Purchased one today but will take 2 weeks to get here due to manufacturing. Ill let ya know howit works once I get it running.

I finally flew my Spot On the last two days. Ten Flights.

A great pattern plane. The O.S. 55 had more tha enough speed to do very axial rolls and all patter maneuvers. I started with a 12x8 APC prop and never needed more than 1/2 throttle. It also was too fast on landing so I switched to a 12x6. Much better landing speed and still needed only 1/2 throttle for all maneuvers.

The final weight was 5.75 pounds which is no problem with the O.S. 55.

Very enjoyable airplane and it uses less than half the fuel of my Venus II.

You can also set up an air brake option for landing - opposite of flaps - up aileron, and down elevator. Start with about 30% up ail, and about 8 to 10% of down ele. Deploy the air brake when you turn base leg, and drag the plane in.

Hope this helps.

Adrian

I have enclosed some pictures. The first is the hole I drilled in the forward bulkhead for the throttle rod. The second is the laser light on the horizontal stab. The wheel pants axil assembly is the last.

Here are some more building pictures.
The extra pushrod tube was for the antenna but I had too much interference from the pull/pull and elevator rods so I had to put the antenna on top of the fuselage.
The O.S. 55 with pitts required minimum cowl cutting.
I used the Dubro pull/pull vs. the cheap hardware supplied.
This is the original version with the aileron servos exposed.
I also epoxy paint the inside of the cowl and wheel pants for strength.
I used a 2/20 blind nut and hex screw to secure the wheel pants.

I had to add 1.5 oz to the tail to balance.

Great flying plane

hi i am getting ready to build this plane and i want to make it electric but am wondering what would be a good motor
thanks

Bigdog,

I converted the Groovy 50, which is the predecessor to the Spot On. Initially, I used an AXI 4120/18 on 5 lithium cells. I believe I used a 14x10 or 14x12 APC-E prop. It was a little heavy, tipping the scales at 6 lbs. I would recommend using mini servos, such as the Hitec 225 or something similar just to save on weight. I also switched the landing gear for a carbon fiber unit. I did away with the receiver pack and used a Castle BEC as well. In the end, I went with a geared Mega 22/20/3 simply because it was a little lighter and I had one available. The weight is now down to 5.5 lbs and it flies quite nicely. Another alternative would be to go with the 4120/14 and a 4 cell lithium. That could also save some more weight. Keep in mind that this are small planes and that weight maters.

Good luck,

Teo

TomTreese, I don't how you got your 55AX to fly well with a 12x8 on it. I tried that and a 12x7, neither worked well. I eventually had to trade it out for an 11x6/7 after it kept dead-sticking on me. I have six friends with the 55AX and none of them can get anything to fly well, or the engine to run correctly, with the 12" props recommended by OS. All are using the 11x7 or 11x8 on their engines. I even tried a 12x6, deadstick! and a 12x5, deadstick & cost me a fuselage/cowl on my GP Extra 300SP. We use APCs.

I had my Spot On 50 for 8 flights. The fuel tank stopper assembly started leaking on flight #4. I traded out the stopper and everything was fine. On flight #8 the winds were around 15mph & gusting a bit. I was 8 mins into the flight, did a right wing low knife edge, then switched to a left wing low knife edge, the wind gusted, and it headed towards the ground. I backed off the throttle, the tail had spun into the wind, and I had the nose in a good, safe, climb. I was just about to add power, and the wind hit it again. Tossed the tail into the air and the nose hit the ground. It broke off the fuselage just in front of the canopy, and the left side of the fuse was crushed from impact force in the tail. The right side was intact. I later found out the winds had been gusting at the field to 24 mph. It was a great flying, point-and-shoot plane, though. Great!.

I have 2 OS-55's and they both ran poorly at mid throttle untill I leaned the low speed needle about 1/2 turn. After you get the high speed set then adjust the low speed till the engine runs smoothly at low and mid throttle. I have seen this on at least five other OS-55's.

I am actually using a 12/6 on the Spot On and 11x7 on the other plane. Both APC props.

Sorry about the crash[&o]. At $149.00 it's probably cheaper to replace than rebuild[]? It's a great flying plane.

Good luck.

Thanks for the info & tip. I'll keep it in mind on the next flight.
The GP Extra 300SP is $199.99. Fuse & tailfeathers = $110 after using a $10 off coupon I had to cover the shipping. The discount is $20 or $25 for TH Super Savers, so it was still cheaper to rebuild. Unusual.

Good flying to you.

I have been following this thread and it got to the point that I picked one up at my local hobby store! What a great looking airplane ! I decided to install a Saito 91 up front so as to have plenty of power on uplines. It balanced just ahead of the recommended 117 mm. No tail weight added and all using the included hardware exept for the rudder pull pull system as I installed the Great Planes Deluxe 2-56 pull pull. The only change I will be making is a new carbon gear later on and a larger fuel tank . I did the maiden flight yesterday at RCACF and it was spectacular ! The Saito with a 14-6 APC has plenty of power and extreme torque for a plane this size. Take off required immediate right rudder ( I think I fed in power way too fast) but otherwise it tracked straight . Climb rate was amazing . Just 3 clicks of aileron trim and 4 of nose up. Tracking is definitely straight . I asked Don Lowe to take the controls and check it out. He was able to do a knife edge loop with no problems and no mixing ! Knige edge requires no correction at all. Up lines are solid with power to spare. Loops are solid round and only slight rudder input on entry. Landing was done with extra speed, I need to work on bleeding the speed off on downwind, did not run out of elevator authority . On the next flight I asked Humberto Pomales (Masters pattern flier and one of the best ) to take it up and he was amazed as how straight it tracked with no mix at all. He put the Spot On through its paces including plenty of snaps and was smiling the whole time and surprised at how the model handled. I am sure I have a winner in my hands ready for Intermediate and Advanced Class ! I'll keep you posted on the next few flights ....

Sound like you have a winner. If you have enough speed to do all the maneuvers. I reduced the prop on mine from 12x8 to 12x6 and it helped with the landing speed. Maybe a 13x6??? I have heard that some of the big pattern flyers will cut the engine on final to slow it down for landing??? Ask Don or Humberto??

I really like the supplied aluminum landing gear. It's the strongest gear set I have ever seen on a ARF. I just replaced the screws with socket heads with lock washers. They have never come loose.

I used some clear dope to cover all the coating tips and seams. This is poor covering and it will come loose of not secured, especially on the bottom when fuel get on it. The only maintainence I have with my plane after 60 flights it re-ironing the covering[&o].

Enjoy this fun A/C.

So I'm just about to pull the trigger on a spot on 50 when I see a you tube video of one flying, and two times during the video it looks as if the plane stalls fairly rapidly dropping a wing, and once the pilot was lucky to recover.

Sooo.. now I'm hesitant....

Have any of you guys that fly this regularly experienced any poor stalling characteristics? Either high speed stalls or low?

I'm used to flying my ultra sport which is (was) really fantastic... lost it due to electrical failure.... so I guess if someone could compare the two that would be great (I know, its unlikely people have flown both)

Thanks,

If the Spot On is balanced both ways ( fore and aft as well as laterally) as mine is, I can't get it to drop a wing in a stall. To do a three turn spin from a stall I have to bump the rudder to drop a wing to beginn the spins. In fact in a hammerhead it will fall backward if I don't use a lot of rudder and bump the throttle. At high speeds the rolls are very axial.

This is a very stable airframe for it's size. One of the best available in this size.

So a slow turn is not an automatic heart attack? Thats good, I'm planning on getting an os55 to put into it so I wantted to make sure its a sweet flyer before I buy the airframe and the engine.

So slow forward flight will just stall straight ahead, anything tricky about flying it? ( I know you already told me no, but just wonder if there is anything I should know)

I have the OS 55 also with a 12x6 prop and you will be more concerned with running out of runway on landing than getting too slow and stalling. With the 12x8 I had to kill the engine to land it.
Pattern planes have very little wind resistance so they will come in fast.

The Spot On, like most pattern planes, is very stable and very easy to glide in for a smooth landing. Just don't force it down and bounce it. Three wheel landings are quite routine.

I have found that my pattern planes are the easiest to land.

does it snap roll with application of full up elevator?

No. It will roll a little right if the elevator throw is excessive because it will stall the airframe. You don't want to be doing high speed snaps with a pattern plane.
If you want to do wild 3D buy a MoJo.

Just bought this kit The N version I believe..Not sure what the diff in N and R is? I have a OS Surpass 70 four stroke just lookin for a home. Do you think the OS would be a good fit in here? Not sure if I should mount it inverted or sideways? Any suggestions?

Joe

If I hade put a 4-stroke in mine it would be inverted and the70 is plenty of engine. 4-stroke don't mind being inverted, in fact I have four 4-strokes inverted in my A/C. 2-Strolkes are a different story. I did that once in a Venus 40. A nightmare. With the inverted 70 there will be very little cowl cutting. It will look and fly great.

The "N" version has the aileron servos burried in the wing and the belly-pan is not attached to the wing. Other than that, no difference.

I thaught I was getting the "N" when I ordered it but received the "A". I was going exchange it till I checked my model. The wings and fuselage were in such perfect condition I kept it.

Tom

That's great news to hear that I wont have trouble with the inverted OS 4 stroke...WHEW. Just got started in the hobby this April and have 14 planes already and my club members say i have the gift of learning fast. Seems like I have flown everything including tail draggin war birds. This will be fun I think

Joe

Flhyr.

Are you sure you want a pattern plane? If you're not into pure pattern flying and or also want to do 3D you may want an Extra or Edge?? The Seagull's are great buys.

The Edge or Extra will do some nice patterns but not as precise at the Venus, Spot On or Focus Sport. Of course the pattern ships will not do a lot of the 3D stuff as well. There is no plane that will do both very well.

You need to decide what's the primary purpose of the plane.

If you want wild and crazy 3D, buy a MoJo.

Ok so I've been flying the heck out of my Spot On 50 and love it ! But...while practicing outside loops the engine has been slow to response at the bottom of the maneuver, it has even quit twice on me . So right now I have plenty of dead stick experience with it, plenty of glide distance for safe landings. I installed a header and moved the main tank aft ( it fits perfectly inside the canopy by cutting a hole in the aft cockpit bulkhead ). On my next flight I had a whole new problem:the engine kept throwing off the prop (it's a Saito 91. 4 strokes love to throw off props if run lean at high end). Richened the mixture as much as possible but the problem remained. Last flight the engine threw the prop off at the worst possible moment: right after rotation ! Pushed the nose down to keep airspeed and managed to land at the end of the runway, ended up in the grass with a damaged right gear attachment. Packed up and headed home.The gear was fixed with a little ingenuity as there is no space to make a repair. So to make sure the engine has proper fuel supply to it I replaced all the brass fuel tubing in the tanks with larger aluminium tubing and new clunks to both tanks. While routing the fuel lines I noticed that my Great Planes fuel filter was missing half of it ! There it was staring at my face....found the other falf on the floor. So all this problems pointed to a lean running engine, seems to me the filter halves had come separated with vibration causing an air leak and leaning the engine ! Tightened the filter and scribbed a line to make sure it wont come loose again.... it's off to work now, test flight tomorrow morning ...